"These chemicals enter the atmosphere at lower latitudes where they were used, and are then deposited down from the cold polar air, so Arctic animals are more highly exposed than animals in more temperate or equatorial regions," says University of Florida researcher Margaret James.
The link between high PCB levels and the less-dense baculum found in polar bear specimens is still under investigation, but study author Christian Sonne is concerned that it could cause some painful issues for the animals when it comes to mating.
"If [the baculum] breaks, you probably won't have a bear which can copulate," says Sonne.
PCBs aren't the only potential problem when it comes to polar bear penises. In an earlier study Sonne found that high levels of another industrial chemical group, organohalogens, were linked to a reduction in the size of the bears' sex organs.